1. Field of Invention
The invention relates to a telescopic tube joint for vacuum cleaner suction tubes or for tripods having at least one outer tube and at least one inner tube. The tube joint includes catch recesses in the inner tube which couple to a catch element in the outer tube. The catch recesses are lockable or unlockable with the catch element via a manually actuated rotary slider attached to and slidably movable around the outer tube.
2. Description of Related Art
In a telescopic tube joint for vacuum cleaner suction tubes according to DE 195 28 814 C1 and DE 195 47 722 C1, the catch element consists of two slidable clamp bodies. The clamp bodies are at opposing acute angles opposite the longitudinal axis of the outer tube on a slanted glide plane of a guide body inserted and form-fitted in a recess of the outer tube engaging in separate catch recesses. The clamp body blocking the respective relative movement of the inner to outer tube is slidable or, in order to release this locked position, is slidable out of its catch recess along its slanted glide plane via the linearly moveable slider. Both clamp bodies are under the influence of a spring, which serves the purpose of keeping both clamp bodies in their locked position. The catch recesses consist of ducts on the outer peripheral surface running diagonally to the longitudinal axis of the tube having a calotte-shaped cross-section, in which the correspondingly rounded clamp bodies are engaged. This telescopic tube joint has proven reliable for vacuum suction tubes. In order to use such a telescopic tube joint not only for vacuum cleaners, but also for tripods, the relatively large space between the catch recesses in the inner tube, on the one hand, as well as the multitude of parts have been perceived to be disadvantageous. In particular, the shortest telescope path is determined by the relatively large space between two catch recesses.
In addition, there is a multitude of different telescopic tube joints in the prior art for tripods, which lock the tubes using spring-loaded latch pins that engage through an opening of the inner tube in a row of holes in the outer tube. Here, the shortest telescope path is determined by the distance of the openings in the outer tube.
In addition, there is a series of telescopic tube joints for tripods that are locked with a force-fit toggle connection. For this purpose, a lever is switched at the respective variably achievable position, which pushes the tubes having a square cross-section force-fit against one another in their locking position. This telescopic tube joint has the considerable disadvantage that only such a force can be exerted, which does not exceed the clamping force of both tubes. When an impelling force is exerted on one or both ends, these tubes tend to slide into one another because the purely force-fit connection is not able to withstand such forces.
In particular for tripods and also for vacuum cleaner suction tubes, tube joints are additionally known that can be continuously adjusted, but are clamped together under frictional force into the respective position using a rotary slide. Unfortunately, the tubes of such joints can slide into one another under an impelling force exerted on one or both ends because this force-fit connection can also not be maintained by the clamping force.